Adjustable helmets have been know in the art for years, and used in different applications such as sports, firefighting, construction work, and the military. In particular, many of these adjustable helmets allow the wearer to adjust the helmet size to fit a particular head. For example, helmet adjustment mechanisms have consisted of a stud and notch or a headband with a rack and pinion adjustment mechanism.
Although these and other conventional adjustment mechanisms have worked well, they have failed in a number of areas. For instance, many prior art designs do not allow the helmet wearer to adjust the size of the helmet while wearing the helmet. Accordingly, the helmet wearer must remove the helmet, adjust the helmet, and retry the helmet size multiple times before a proper fit can be established.
Moreover many prior art adjustment mechanisms present a risk of being accidentally actuated which can leave the wearer susceptible to injury.